According to a conventional signal transmission technique, waves (such as a sine wave or a square wave) with a same period are usually used to distinguish bit 1 and bit 0 specifically by different duty ratios within the same period. The duty ratio refers to a proportion of a high level in a period.
According to the conventional signal transmission technique, a signal sending end transmits waves (such as the sine wave or the square wave) with the same period, a signal receiving end receives the waves (such as the sine wave or the square wave) with the same period sent by the signal sending end and detects the duty ratio thereof to distinguish bit 1 and bit 0 and thereby determines data transmitted by the signal sending end. However, a process of detecting the duty ration is comparatively complicated, which increases a workload and cost for the signal receiving end.